Efforts to improve PV (photovoltaic) devices, particularly those devices that are integrated into building structures (e.g. photovoltaic sheathing elements, spacer pieces, edge pieces), to be used successfully, should satisfy a number of criteria. The PV devices may be commonly known as Building-integrated photovoltaics (BIPV). These BIPVs are typically PV devices (and associated system components) that are used to replace conventional building materials in parts of the building envelope such as the roof, skylights, or facades. The PV device and the array as installed should be durable (e.g. long lasting, sealed against moisture and other environmental conditions) and protected from mechanical abuse over the desired lifetime of the product, preferably at least 15 years, more preferably at least 25 years. The device should be easily installed into the array of devices (e.g. installation similar to conventional roofing shingles or exterior wall coverings) or replaced (e.g. if damaged).
BIPVs have increased in popularity significantly in areas that desire premium aesthetics. Having the photovoltaic material appear integral to the roof line presents challenges as it displaces the standard roofing materials which are of a very different material.
Most BIPVs sold today are designed to meet a performance warranty of at least 15 to 25 years and an expected service life beyond this. The life of the BIPVs appears to exceed the expected life of a traditional asphalt shingle (e.g. 10-16 years). When comparing the BIPVs to a premium roofing material such as concrete tile or natural state, the BIPV's life may be below that of the natural roof; suggesting the BIPVs will be replaced first.
These different life cycles may result in the different roofing materials being removed and replaced in different time intervals. If both materials are replaced together, the expense of the repair could include the cost of both. While one may believe it would be ideal if the photovoltaic material could cover the entire roof, this is unlikely due to building codes and roofing complexity. Therefore, standard roofing materials are used for safety (access areas, shaded areas, etc), ease of interface (around vent stacks, dormers, etc) and to reduce overall roofing cost.
This presents the problem of having two very different materials on the roof top at the same time, one material requiring standard roofing experience, the other requiring photovoltaic experience. This also may prevent maintenance on one or the other material without the other tradesman being present. To make this full package desirable to the consumer, and to gain wide acceptance in the marketplace, the system should be inexpensive to build and install. The present invention may help alleviate the problems discussed above and facilitate lower generated cost of energy, making PV technology more competitive relative to other means of generating electricity.
Among the literature that can pertain to this technology include the following patent documents: WO/2009/137353A3; WO/2009/137352A3; WO/2009/137348A3; and WO/2009/137347A3; all incorporated herein by reference for all purposes and particularly for teachings on photovoltaic roofing or building sheathing element, arrays, and connectors.